I of the Dragon has a single-player campaign. You work through it land by land, but every land remains somewhat dynamic even when you're not there. There is (or you build) a town in each land. I don't know exactly what they do for you, but you help them grow and protect them from evil. Of course as you conquer more lands, it becomes harder to maintain all of them, there being only one of you. But at least there's infinate leveling with spawning creatures!
